Solid-vapor sorption systems, such as those described in the aforesaid application, are used for cooling and refrigeration. These systems range from small devices having a cooling power of a few watts, to relatively large systems producing megawatts of cooling. The larger systems, for example used in commercial HVAC applications, are usually designed to reject heat by using heat transfer fluids directed to air coils, air-cooled condensers, evaporative condensers, cooling towers, or to ground or surface water. Pumped loops for transferring sorber heat to such heat rejection means are well-known to those skilled in the art. However, in relatively small systems, such as appliances disclosed in U.S. Pat. No. 5,161,389, and in apparatus for electronic cooling disclosed in aforesaid application Ser. No. 07/794,501, the use of extra cooling loops, and/or pump loops for transferring sorber heat to heat rejection is not practical.
In operating sorption systems described in the aforesaid patent and co-pending application as well as other sorption systems in which a gaseous reactant is adsorbed on a solid reactant, suitable components must be provided to reject heat. Systems in which the gaseous reactant is alternately adsorbed on and desorbed from the adsorbent provide two sources of heat which must be rejected during continuous operation: heat of condensation of the refrigerant, and heat of adsorption at the adsorbing reactor. Preferably, means for rejecting heat to the atmosphere with no or minimal electrical power consumption are provided. For example, heat of condensation can usually be rejected in an air-cooled condenser, using natural or forced convection over the condenser coil.
In the sorption solid-vapor reaction system using single or multiple sorbers to alternately adsorb and desorb refrigerant, conflicting heat transfer requirements must be considered and satisfied. In the desorption phase, it is desirable to utilize all of the energy from the heating means for driving the desorption reaction. The sorber may be insulated or otherwise provided with means for minimizing the heat loss since any heat losses to the environment reduce overall system efficiency and increase size and capacity requirements of the heat source. On the other hand, during the adsorption phase, efficient heat removal from the sorber is necessary, and must be transferred from the sorber to a heat rejection component, or be rejected directly from the sorber itself. The problem is exacerbated by the fact that elevated desorption temperatures create sorber-to-ambient temperature differentials favoring heat losses precisely at the time when such heat loss is undesirable.